Nuclear waste concern

The “spent fuel” issue at Koeberg Nuclear Power Station, along with every other similar power station around the world, is increasingly becoming a serious concern.

There are currently in the region of 1 400 tons of spent fuel stored at Koeberg, and nobody knows what the best way to dispose of it is.

The number of pools in which these highly radioactive rods are stored are few, and Eskom has recently said they have resorted to “triple-stacking”, in which three times the amount of rods are stored in any single pool.

These pools do two things – provide cooling and radiation shielding.

Roughly every seven centimeters of water cuts the amount of radiation in half.

Koeberg insist that nuclear waste is “extremely well managed throughout the world, probably managed better than any other waste”.

But what happens to the incredibly radioactive rods in the long term remains unknown.

Peter Becker from the Koeberg Alert Alliance says: “Nobody knows! It is kept under water for a few years and then when it becomes a little safer these are placed in dry-cask storage.”

He adds that the word “safer” is relative, since the rods are still extremely radioactive, and would stay that way for thousands of years.

“Koeberg needs about 30 tons of uranium ore fuel rods to operate. These rods decay over time, but the 1 % spent plutonium, which is the main ingredient for nuclear bombs, remains radioactive for 10 – 20 000 years,” continues Becker.

“Koeberg opened in 1984 and they originally said that within five years the conundrum around spent fuel would have been solved. We were recently told during the Public Safety Information Forum on 27 March that the issue would be resolved in five years time.”

According to Becker the danger exists that the combination of over-stacked pools and a natural disaster such as an earthquake or a tsunami could pose a serious nuclear threat to large parts of Cape Town.

Eskom’s Stakeholders Management Manager, Lewis Phidza, says there are currently 2 117 elements of spent fuel, of which 112 are in dry storage casks, 1 009 in the Unit 1 spent fuel pool and 996 in the Unit 2 spent fuel pool.

Each fuel element has a total mass of 670 kg.

Phidza adds: “Although the plant was designed for an operating life of 40 years, the original fuel rack capacity of the spent fuel pools was only for four fuel cycles. These spent fuel pools have been re-racked twice in the past to increase the used fuel storage capacity. The re-racking and expansion of the storage capacity of spent fuel pools is a normal international practice performed to international standards and regulated by the national nuclear regulatory body in each country (the National Nuclear Regulator for South Africa).”

He adds that Koeberg spent fuel cooling systems are designed with independent cooling pumps and heat exchangers.

“Various enhancements have been made over the years to the spent fuel pool cooling systems, including the installation of an additional cooling circuit (cooling pump and heat exchanger) and the installation of emergency water make-up systems to the spent fuel pools,” says Phidza.

He insists that spent fuel and all radioactive waste arising from nuclear power operations are “extremely well managed throughout the world”.

According to him countries that produce used nuclear fuel either recycle (recover the uranium and plutonium) and dispose of it in deep geological repositories, or directly dispose of it in these geological depositories without recycling it, or finally with continued interim storage.

He concludes: “In April this year the Minister of Energy launched the National Radioactive Waste Disposal Institute that is tasked with the siting, construction and operation of radioactive waste and spent fuel disposal facilities on a national basis.”

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